Imaging Fourier Transform Spectroscopy of the Boundary Layer Plume from Laser Irradiated Polymers and Carbon Materials

摘要

Emissive plumes from laser irradiated fiberglass reinforced polymers (FRP), poly(methyl methacrylate) (PMMA) and porous graphite targets were investigated primarily using a mid wave infrared (MWIR) imaging Fourier transform infrared (FTIR) spectrometer. Polymer and graphite targets were irradiated with a 1.064 micrometer Nd:YAG and a 1.07 micrometer ytterbium continuous wave (CW) fiber lasers respectively. Data was acquired with a spectral resolution of 2 cm-1 and spatial resolution as high as 0.52 mm2 per pixel. Strong emissions from H2O, CO, CO2 and hydrocarbons were observed in the MWIR between 1900 cm-1 and 4000 cm- 1. A single-layer radiative transfer model was developed to estimate spatial maps of temperature and column densities of CO and CO2 from the hyperspectral imagery of the boundary layer plume of irradiated FRP and porous graphite targets. The spectral model was used to compute the absorption cross sections of CO and CO2 using spectral line parameters from the high temperature extension of the HITRAN. Also, spatial maps of plume temperature and methyl methacrylate (MMA) column density were developed for laser irradiated black PMMA.